Workpiece hold-down jaws with constant dimension

ABSTRACT

A hold-down for workpieces including a bed and a pair of upstanding opposed jaws mounted thereon with at least one jaw being movable in relation to the other with at least one jaw also including a structure which will exert a downward force on the workpiece when the jaws are moved toward each other into clamping engagement with the workpiece to assure positive contact of the workpiece with the bed of the hold-down, parallel or the like. The means exerting the downward force includes engaging inclined surfaces and engageable flat surfaces which will come into contact when the movable component of the jaw has reached a predetermined position in its downward movement thereby providing a predetermined dimension for the jaws which is necessary in many machine operations.

United States Patent [191 Lassy et al.

[ Jan. 15, 1974 Grove Ave., Forestville, Conn. 06010 [22] Filed: Apr. 1, 1971 [21] Appl. No.: 130,394

521 U.S.Cl. 269/136, 269/138 51 Int.Cl B23q 3/02 58 FieldofSearch 269/136, 138

[56] References Cited UNITED STATES PATENTS 2/1942 Odin Primary Examiner-Harold D. Whitehead Assistant Examiner-E. F. Desmond Att0rneyClarence A. OBrien and Harvey B. Jacobson [5 7 ABSTRACT A hold-down for workpieces including a bed and a pair of upstanding opposed jaws mounted thereon with at least one jaw being movable in relation to the other with at least one jaw also including a structure which will exert a downward force on the workpiece when the jaws are moved toward each other into clamping engagement with the workpiece to assure positive contact of the workpiece with the bedof the hold-down, parallel or the like. The means exerting the downward force includes engaging inclined surfaces and engageable flat surfaces which will come into contact when the movable component of the jaw has reached a predetermined position in its downward movement thereby providing a predetermined dimension for the jaws which is necessary in many machine operations.

7 Claims, 6 Drawing Figures PATENIEnm 15 ran 3, 785.535

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PMENTEnm 15 m4 SHEEYQWQ W 1 W a A M u L A n m H w. 0 W a HH 7 n mm HEW J 5. l 7 Wm m Q n WW 3m 1 WORKPIECE HOLD-DOWN JAWS WITH CONSTANT DIMENSION BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a holddown for workpieces and represents certain improvements in prior U.S. Pat. No. 3,5 14,092, issued May 26, 1970 and in copending application U. S. Ser. No. 39,652, filed May 22, 1970, now U.S. Pat. No. 3,738,638, issued June 12, 1973.

2. Description of the Prior Art As set forth in prior U.S. Pat. No. 3,514,092, workpiece hold-down devices are known which introduce a downward force onto the workpiece when the workpiece holder is actuated. Such devices move the workpiece downwardly against the bed of the vise or other gripping device or downwardly against parallels or the like and in order to assure positive contact with the seat, machine operators frequently tap the workpiece downwardly by the use of a hammer or other suitable impact implement. Such hammering is not only time consuming but sometimes results in damage to the workpiece, damage to the bed of the vise, parallels or other seat which the workpiece contacts. Also, the vise jaws having a movable component result in the jaws having variable dimensions to the effective clamping edge of the jaw. Also, such movable components sometimes will not effectively grip a workpiece when the workpiece is positioned adjacent the upper edge of the jaws which tends to cause the movable component of the jaw to tip or tilt.

SUMMARY OF THE INVENTION An object of the present invention is to provide a workpiece hold-down such as a vise or the like having relatively movable jaws for gripping a workpiece with either or both jaws having a relatively vertically movable component with both components of the jaws having mating angled or inclined surfaces which will automatically cause downward movement of the vertically movable component when clamping pressure is exerted against a workpiece positioned between the jaws thereby assuring positive contact between the workpiece and its seat which may be either the bed of the vise, parallels or other precision surface.

Another object of the invention is to provide hold down jaws in which both components of the jaw include mating flat surfaces which limit the downwardly angular movement of the movable component to a predetermined constant distance thus assuring constant predetermined-dimension to the edge of the jaw and of the workpiece with this constant dimension being essential in many machine operations.

A further object of the invention is to provide a workpiece hold-down in accordance with the preceding objects in which the relatively movable component of the jaw is guided and spring biased to an upper position with the mating inclined surfaces and flat surface stabilizing the vertically movable component to enable effective gripping of a workpiece even when it is held at the very top extremity of the vise jaws thereby eliminating tipping of the jaws.

Still another object of the invention is to provide a workpiece hold-down which is relatively simple in construction, long lasting and efficient in use, positive in applying a holddown force and maintaining a constant dimension and yet relatively inexpensive to manufacture.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of a workpiece holddown vise illustrating the jaws of the present invention incorporated therein.

FIG. 2 is an exploded, group perspective view of a jaw assembly.

FIG. 3 is an enlarged sectional view illustrating the workpiece hold-down with the gripped workpiece disposed at the upper edge of the jaws.

FIG. 4 is a side elevational view, on an enlarged scale, of a jaw illustrating the relationship of the components.

FIG. 5 is a vertical sectional view taken substantially upon a plane passing along section line 5-5 of FIG. 4 illustrating further structural details of the guiding structure.

FIG. 6 is a fragmental plan view of the jaw.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now specifically to the drawings, the workpiece hold-clown device in which the present invention is incorporated is generally designated by the reference numeral 10 and is in the form of a vise which holds a workpiece 12. The vise is of conventional construction and includes relatively movable jaws 14 and 16 with the jaw 14 usually being stationary and the jaw 16 usually being movable in relation thereto with a suitable mechanism 18 being provided for moving the jaw 16. The vise also includes a precision surface 20 in the form of a bed or base which supports a pair of parallels 22 which are of known construction and provided with precision edge surfaces for supporting the workpiece 12 with it being understood that the workpiece 12 could also be engaged directly with the precision surface 20 depending upon the configuration and size thereof.

Each of the jaws l4 and 16 of the vise 10 includes a hold-down jaw 24 mounted fixedly thereon in any suitable manner. Each hold-down jaw 24 includes a base section 26 which is stationary with respect to the vise jaw 14 or 16 and a movable section 28 which is vertically movable in relation to the section 26. For purposes of description, the section 26 will be considered a stationary component while the section 28 will be considered a movable component with it being understood that the entire jaw assembly 24 will be reciprocated horizontally if mounted on either of the vise jaws 14 or 16 which moves to grip the workpiece 12. As illustrated in FIG. 2, the stationary section 26 and the movable section 28 each are constructed of elongated generally rectangular bodies with the section 26 having a pair of vertically spaced angled or inclined surfaces 30 and 32 which are interconnected by a vertical surface 34 which is substantially flat. As illustrated, the two inclined surfaces 30 and 32 are parallel to each other with the outer and upper edges of each surface lying in the same vertical plane outwardly beyond the vertical flat surface 34 and the inner and lower edges of the inclined surfaces 30 and 32 are disposed laterally inwardly of the vertical surface 34 as illustrated in FIGS. 3 and 4.

The movable section 28 is provided with corresponding and mating inclined surfaces 36 and 38 and a vertically disposed flat intermediate surface 40 therebetween with the relationship of the surfaces 36 and 38 with the surface 40 being the same as in the stationary section 26. With this construction, with the inclined surfaces engaging each other, when the movable section 28 is in its uppermost position as illustrated in FIG. 4, the vertical surfaces 34 and 40 will be spaced apart. When lateral force is exerted by the vise jaw such as when gripping the workpiece 12, such lateral force will cause the inclined surfaces to move the movable section 28 downwardly thus also moving the gripped workpiece 12 downwardly. This downward movement will continue until the flat surface 40 comes into engagement with the matingflat surface 34 at which time the downward movement of the movable section 28 will no longer occur. This fixed engagement between the flat surfaces will enable a constant repetition of the amount of movement of the movable section 28 thereby providing a predetermined dimension to the gripping surface of the jaw assembly 24 so that the over-all horizontal thickness of the jaw 24 will be constant each time a workpiece is engaged. This provides for an absolute precision gripping surface for the jaw 24 and a precision dimension for the jaw which will be repeated each time the jaw is operated to clamp the workpiece.

The constant dimension is illustrated in FIG. 3 and the retention of this constant dimension to the edge of the jaw and workpiece is necessary in many machine operations.

interposed between the sections 26 and 28 is a pair of stop pins 42 which are anchored to the stationary section and received in enlarged recesses or blind bores 44 in the flat surface 40 of the movable section 28 to limit the upward movement of the movable section 28 thus serving as stop pins to limit the vertical movement and thus limit the inward movement of the movable section 28 when the workpiece 12 is not being gripped. The stop pins do not serve as a stop when the workpiece is being gripped since the mating flat surfaces 40 and 34 will become engaged before the stop pin 42 engages the upper limit of the bore 44. A tension spring 46 is provided at each end of the jaw 24 and is upwardly inclined from an anchor pin 48 on the movable section 28 to an anchor pin 50 on the stationary section 26 thus biasing the movable section 28 upwardly when the workpiece 12 is not being gripped. The spring 46 is received in an inclined groove or recess 52 in the ends of the jaw sections 26 and 28 with the dimensions of the groove 52 being sufficient to enable movement of the movable jaw section 28 without coming into shearing contact with the spring 46.

The stationary section 26 is provided with a pair of chip and dust shields 54 in the form of flat plates secured to the end edges of the stationary section 26 by suitable fasteners 56 and overlapping the ends of the movable section 28 thus precluding entry of foreign material between the mating surfaces of the sections 26 and 28.

The parallels 22, when used, are provided with a recess or groove 58 in the inner edge thereof for matching registry with a corresponding recess or groove 60 to provide a space for receiving a retaining clip 62 which has the converging legs thereof received in bores 64 in the bottom of the recesses 58 and 60 thus mounting the parallel from the movable section 28 without restricting movement of the movable section 28. Thus, the parallels 22 will support the workpiece 12 and the precision surfaces of the parallel will provide a precision surface for supporting the workpiece 12. When the workpiece 12 is engaged by the jaws 24, the movable section 28 of each of the jaws is at its upper limit of movement in which the upper surface generally is parallel to the upper surface of the stationary section 26 as illustrated in FIG. 4. Then, when the mechanism 18 of the vise is actuated, inward forces are exerted by the jaws 24 and such inward forces will cause positive downward movement of the movable section 28 thus positively forcing the workpiece l2 downwardly against the parallels. The downward movement of the movable section 28 ceases when the flat surfaces 40 and 34 come into engagement as illustrated in FIG. 3 thus assuring positive seating of the workpiece against the parallels 22 or against the precision surface 20 in the event parallels are not used. The two spaced inclined surfaces as well as the flat mating surfaces will retain the movable section 28 in an upright position even when the workpiece 12 is gripped by the extreme upper end edge of the jaws as illustrated in FIG. 3. Also, the surfaces retain the distance to the gripping edge of the jaw 24 a constant dimension and a dimension which is repeated during repeated positioning of workpieces in the vise.

The hold-down assembly 24 is self-contained and may be used singly or in pairs and either attached to or not attached to the vise and either with or without parallels thereby greatly increasing the versatility and uses thereof. Also, the self contained jaw has a narrow width or thickness thereby allowing for greater work capacity in the vise when used. This narrowness of width is obtained by use of the two angled or inclined surfaces with it being clear that a single inclined surface extending throughout the height of the jaw would greatly increase the width or thickness of the jaw assembly.

Various spring and other equivalent structures may be employed for returning the movable section 28 to its retracted position and this device may be used in various utilities other than in vises such as various jigs, fixtures, lathe chuck jaws and the like to insure contact of the workpiece with a precision surface such as the face of a chuck jaw surface or the like.

The foregoing is considered as illustrative only of the principles of the invention. Further,-since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

What is claimed as new is as follows:

1. A workpiece hold-down device comprising a bed, a pair of opposed jaws associated with and extending upwardly from said bed with at least one of said jaws being movable for gripping and releasing a workpiece positioned between gripping surfaces thereon, at least one of said jaws including a movable component supported for downward movement in relation to the jaws and bed when exerting a clamping force against the workpiece thereby exerting a downward force on the workpiece in response to a gripping force being exerted on the workpiece by said jaws, means for causing downward movement including cam means operative in response to lateral force being exerted on the work piece to move the movable component downwardly, and means limiting downward movement of the movable component to a predetermined position for providing a predetermined constant total thickness of said jaw, said cam means including a pair of vertically spaced transversely extending inclined surfaces on the movable component, said jaw including a stationary component having a pair of vertically spaced mating inclined surfaces engaged with the inclined surfaces on the movable component whereby the movable component is urged downwardly and toward the stationary component when clamping force is exerted on the workpiece by the jaws, said means limiting downward movement of the movable component including coacting flat vertical surfaces between the inclined surfaces on the movable and stationary components of the jaw for engagement when the movable component moves downwardly and toward the stationary component a predetermined distance thereby providing a constant predetermined total thickness of the movable and stationary components of the jaw, resilient means interconnecting the movable component and the stationary component for biasing the movable component upwardly and retaining the mating inclined surfaces in constant contact with each other, and means interconnecting the movable component and the stationary component including a tension spring member interconnecting the components at the end edges thereof and applying a force to the movable component for moving it upwardly and maintaining the mating inclined surfaces in engagement and being disposed between the vertically spaced, mating inclined surfaces thereby leaving the inclined surfaces uninterrupted.

2. The structure as defined in claim 1 together with means interconnecting the movable component and the stationary component for limiting the upward movement of the movable component gripping surfaces when not gripping a workpiece.

3. The structure as defined in claim 2 wherein said means limiting upward movement of the movable component includes a pin rigid with one of the components and a blind bore larger than the pin in the other component with the pin and bore being dimensioned sufficient to enable completely free movement of the movable component in a downward direction but limiting the upward movement of the movable component.

4. A workpiece hold-down device comprising a bed, a pair of opposed jaws associated with and extending upwardly from said bed with at least one of said jaws being movable for gripping and releasing a workpiece positioned between gripping surfaces thereon, at least one of said jaws including a movable component supported for downward movement in relation to the jaws and bed when exerting a clamping force against the workpiece thereby exerting a downward force on the workpiece in response to a gripping force being exerted of the workpiece by said jaws, means for causing downward movement including cam means operative in response to lateral force being exerted on the workpiece to move the movable component downwardly, and means limiting downward movement of the movable component to a predetermined position for providing a predetermined constant dimension between the gripping surfaces of the jaws, said cam means including a pair of vertically spaced transversely extending inclined surfaces on the movable component, said jaw including a stationary component having a pair of vertically spaced mating inclined surfaces engaged with" the inclined surfaces on the movable component whereby the movable component is urged downwardly and toward the stationary component when clamping force is exerted on the workpiece by the jaws, said means limiting downward movement of the movable component including coacting flat vertical surfaces between the inclined surfaces on the movable and stationary components of the jaw for engagement when the movable component moves downwardly and toward the stationary component a predetennined distance thereby providing a constant predetermined total thickness of the stationary and movable components of the jaw, resilient means interconnecting the movable component and the stationary component for biasing the movable component upwardly and retaining the mating inclined surfaces in constant contact with each other, means interconnecting the movable component and the stationary component for limiting the upward movement of the movable component to provide a predetermined dimension between the jaw gripping surfaces when not gripping a workpiece, said means limiting upward movement of the movable component including a pin rigid with one of the components and a blind bore larger than the pin in the other component with the pin and bore being dimensioned sufficient to enable completely free movement of the movable component in a downward direction but limiting the upward movement of the movable component, and a parallel positioned between the bed and workpiece and including precision surfaces engaging the bed and workpiece, means connecting the parallel to the movable component alongside the workpiece gripping surface, the parallel having a vertical dimension less than the movable component when in its gripping position, the two vertically spaced inclined surfaces and vertical surfaces on the movable and stationary components stabilizing the movable component to enable gripping of the workpiece at the extreme upper edge of the movable component without tipping of the movable component in relation to the stationary component.

5. The structure as defined in claim 4 wherein said mating inclined surfaces are continuous-and uninterrupted completely from end to end of the movable and stationary components, said vertical surface between the inclined surfaces being disposed in a plane spaced laterally from the adjacent edge portions of the inclined surfaces whereby the vertical surfaces will be engaged before the mating inclined surfaces have moved downwardly and inwardly to the full extent that would be permitted by the inclined surfaces.

6. In a workpiece gripping and hold-down device, a jaw assembly comprising a base section and a workpiece gripping section, each of said sections having a pair of vertically spaced inclined vsurfaces extending continuously and uninterruptedly from end to end of the sections for causing downward movement of the workpiece gripping section in relation to the base section when clamping force is exerted on a workpiece engaged by the workpiece gripping section, each of said sections of the jaw assembly including a vertical surface oriented between the inclined surfaces with the vertical surface being spaced laterally of the adjacent edge portions of the inclined surfaces whereby the vertical surfaces will be engaged with each other prior to the inclined surfaces moving to the extreme position permitted thereby, resilient means interconnecting said secerting a gripping force on a workpiece to provide a precision dimension to the workpiece gripping surface of the jaw assembly.

7. The structure as defined in claim 6 wherein said tions exerting a force to bias the workpiece gripping jaw assembly is self-contained and capable of use singly or in opposed pairs, the continuity of the force transmitting surfaces between the sections of the jaw assembly enabling the jaw assembly to be constructed with a minimum thickness thereby maintaining a greater workpiece receiving capacity. 

1. A workpiece hold-down device comprising a bed, a pair of opposed jaws associated with and extending upwardly from said bed with at least one of said jaws being movable for gripping and releasing a workpiece positioned between gripping surfaces thereon, at least one of said jaws including a movable component supported for downward movement in relation to the jaws and bed when exerting a clamping force against the workpiece thereby exerting a downward force on the workpiece in response to a gripping force being exerted on the workpiece by said jaws, means for causing downward movement including cam means operative in response to lateral force being exerted on the workpiece to move the movable component downwardly, and means limiting downward movement of the movable component to a predetermined position for providing a predetermined constant total thickness of said jaw, said cam means including a pair of vertically spaced transversely extending inclined surfaces on the movable component, said jaw including a stationary component having a pair of vertically spaced mating inclined surfaces engaged with the inclined surfaces on the movable component whereby the movable component is urged downwardly and toward the stationary component when clamping force is exerted on the workpiece by the jaws, said means limiting downward movement of the movable component including coacting flat vertical surfaces between the inclined surfaces on the movable and stationary components of the jaw for engagement when the movable component moves downwardly and toward the stationary component a predetermined distance thereby providing a constant predetermined total thickness of the movable and stationary components of the jaw, resilient means interconnecting the movable component and the stationary component for biasing the movaBle component upwardly and retaining the mating inclined surfaces in constant contact with each other, and means interconnecting the movable component and the stationary component including a tension spring member interconnecting the components at the end edges thereof and applying a force to the movable component for moving it upwardly and maintaining the mating inclined surfaces in engagement and being disposed between the vertically spaced, mating inclined surfaces thereby leaving the inclined surfaces uninterrupted.
 2. The structure as defined in claim 1 together with means interconnecting the movable component and the stationary component for limiting the upward movement of the movable component gripping surfaces when not gripping a workpiece.
 3. The structure as defined in claim 2 wherein said means limiting upward movement of the movable component includes a pin rigid with one of the components and a blind bore larger than the pin in the other component with the pin and bore being dimensioned sufficient to enable completely free movement of the movable component in a downward direction but limiting the upward movement of the movable component.
 4. A workpiece hold-down device comprising a bed, a pair of opposed jaws associated with and extending upwardly from said bed with at least one of said jaws being movable for gripping and releasing a workpiece positioned between gripping surfaces thereon, at least one of said jaws including a movable component supported for downward movement in relation to the jaws and bed when exerting a clamping force against the workpiece thereby exerting a downward force on the workpiece in response to a gripping force being exerted on the workpiece by said jaws, means for causing downward movement including cam means operative in response to lateral force being exerted on the workpiece to move the movable component downwardly, and means limiting downward movement of the movable component to a predetermined position for providing a predetermined constant dimension between the gripping surfaces of the jaws, said cam means including a pair of vertically spaced transversely extending inclined surfaces on the movable component, said jaw including a stationary component having a pair of vertically spaced mating inclined surfaces engaged with the inclined surfaces on the movable component whereby the movable component is urged downwardly and toward the stationary component when clamping force is exerted on the workpiece by the jaws, said means limiting downward movement of the movable component including coacting flat vertical surfaces between the inclined surfaces on the movable and stationary components of the jaw for engagement when the movable component moves downwardly and toward the stationary component a predetermined distance thereby providing a constant predetermined total thickness of the stationary and movable components of the jaw, resilient means interconnecting the movable component and the stationary component for biasing the movable component upwardly and retaining the mating inclined surfaces in constant contact with each other, means interconnecting the movable component and the stationary component for limiting the upward movement of the movable component to provide a predetermined dimension between the jaw gripping surfaces when not gripping a workpiece, said means limiting upward movement of the movable component including a pin rigid with one of the components and a blind bore larger than the pin in the other component with the pin and bore being dimensioned sufficient to enable completely free movement of the movable component in a downward direction but limiting the upward movement of the movable component, and a parallel positioned between the bed and workpiece and including precision surfaces engaging the bed and workpiece, means connecting the parallel to the movable component alongside the workpiece gripping surface, the parallel having a vertical dimension less than the movable component when in its gripping position, the tWo vertically spaced inclined surfaces and vertical surfaces on the movable and stationary components stabilizing the movable component to enable gripping of the workpiece at the extreme upper edge of the movable component without tipping of the movable component in relation to the stationary component.
 5. The structure as defined in claim 4 wherein said mating inclined surfaces are continuous and uninterrupted completely from end to end of the movable and stationary components, said vertical surface between the inclined surfaces being disposed in a plane spaced laterally from the adjacent edge portions of the inclined surfaces whereby the vertical surfaces will be engaged before the mating inclined surfaces have moved downwardly and inwardly to the full extent that would be permitted by the inclined surfaces.
 6. In a workpiece gripping and hold-down device, a jaw assembly comprising a base section and a workpiece gripping section, each of said sections having a pair of vertically spaced inclined surfaces extending continuously and uninterruptedly from end to end of the sections for causing downward movement of the workpiece gripping section in relation to the base section when clamping force is exerted on a workpiece engaged by the workpiece gripping section, each of said sections of the jaw assembly including a vertical surface oriented between the inclined surfaces with the vertical surface being spaced laterally of the adjacent edge portions of the inclined surfaces whereby the vertical surfaces will be engaged with each other prior to the inclined surfaces moving to the extreme position permitted thereby, resilient means interconnecting said sections exerting a force to bias the workpiece gripping section toward the base section and also bias the workpiece gripping section in a direction whereby the inclined surfaces move the workpiece gripping section so that the vertical surfaces are spaced from each other thereby enabling the vertical surfaces to limit lateral movement of the workpiece gripping section when exerting a gripping force on a workpiece to provide a precision dimension to the workpiece gripping surface of the jaw assembly.
 7. The structure as defined in claim 6 wherein said jaw assembly is self-contained and capable of use singly or in opposed pairs, the continuity of the force transmitting surfaces between the sections of the jaw assembly enabling the jaw assembly to be constructed with a minimum thickness thereby maintaining a greater workpiece receiving capacity. 